Heretofore, medical treatment of excising an atheroma arising in a blood vessel by inserting a catheter into the blood vessel has been performed. The catheter for use in the medical treatment has an opening in the side wall. The catheter is inserted into the blood vessel to a position where the opening faces the atheroma. Then, when a balloon provided near the opening is expanded, the opening comes close to the atheroma, and then the atheroma enters a lumen of the catheter through the opening. In the lumen of the catheter, a cutter is provided movably in the axial direction. The cutter is driven by a motor to be rotated in the lumen. Due to the fact that the cutter is made to move in the lumen while being rotated, the atheroma entering the lumen is excised. The excised atheroma is stored in the lumen of the catheter (Citation List 1 and 2).
The catheter described above is inserted into the blood vessel while being guided by a guide wire. For example, in the coronary artery, the blood vessel itself curves in many cases, and therefore when the catheter is inserted into the blood vessel, the distal end of the catheter contacts the inner wall of the blood vessel in many cases. Therefore, it is desired that the distal end of the catheter has such flexibility that the distal end of the catheter follows the shape of the blood vessel and does not damage the inner wall of the blood vessel. For example, a so-called nose cone is known as the structure of the distal end of the catheter (Patent Literature 3). The nose cone is a structure in which a spiral wire is provided as the core in a resin tube. Moreover, a marker detectable by X-rays is provided on the distal end of the nose cone.